$ { \left[\begin{array}{rrr}{-1} & {0} & {-1} \\ {3} & {-2} & {0}\end{array}\right]+\left[\begin{array}{rrr}{0} & {2} & {-2} \\ {1} & {2} & {2}\end{array}\right] = {?} } $
Solution: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{-1}+{0} & {0}+{2} & {-1}+{-2} \\ {3}+{1} & {-2}+{2} & {0}+{2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-1} & {2} & {-3} \\ {4} & {0} & {2}\end{array}\right]}$